Nondusting compositions containing stabilized diazo compounds



Patented July 26, 1949 NONDUSTI NG COMPOSITIONS CONTAINING STABILIZED DIAZO COWOUNDS Herman A. Bergstrom, Albany, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a. corporation of Delaware No Drawing. Application December 27, 1946,

Serial No. 718,906

7 Claims. (Cl. 260-1d1) This invention relates to a process for reducing dusting in powders, more particularly in powders of organic color compounds, chromogens and auxochromic compounds and to dustless compositions of the same.

It is customary in the manufacture oforganic color compounds, i. e., dyestuffs and or anic pigments, and of 'chromogens and auxochromic compounds to prepare these materials in powder form asin this way economy and convenience in shipping and handing of the products is to be obtained. These advantages in the powder form of the products are offset to some extent by the tendency of the products to become objectionably dusty in handling, a condition brought about by air-lifting of very fine product particles which are always present in the powders. The degree of the dusting will vary depending on the concentration of very fine particles in the powders and on the conditions surrounding the handling of the powders, such as the presence and magand measuring are difficult while in extreme cases accurate measurement is sometimes a practical impossibility due to loss of material.

I have now found that dustiness in pulverulent organic color compounds, chromogens' and auxichromic compounds may be overcome in an advantageous manner by incorporating therewith a minor proportion of a liquid dialkyl carbonate having at least 5 carbon atoms.

These dialkyl carbonates contain an aggregate of at least 4 carbon atoms in the alkyl groups and under normal pressure boil at a. temperature above 125 C. 'They exhibit toward the oragnic color compounds, chromogens and auxochromic compounds, non-reactivity, but a slight solvent action, non-interference with their use in the role of colorant, chromogen or auxochromic compound as the case may be, and a high degree of permanency in respect to the dust-binding effect. Among dialkyl carbonates which may be employed as dust-binding agents in the process of the invention may be mentioned, for example,

diethyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, dipropyl carbonate, ethylisopropyl carbonate, dibutyl carbonate, ethyl-secbutyl carbonate, di-sec-butyl carbonate, di-isobutyl carbonate, methylisobutyl carbonate, ethylisobutyl carbonate, methyl-sec-n-amyl carbonate, si-lsoamyl carbonate, etc. a

The amount of the liquid dialkyl carbonates used in treating the powders in accordance with the invention may. b varied. Positive results in dust reduction may be obtained with as little as 0.5% of one of the dialkyl carbonates on the weight of the powder.- Optimum amounts range from about 1 to 3% by weight. although in some instances for best results up to about 5% by weight may be required. Where economically feasible. still larger amounts may be used with excellent results, for example between about 5 and 10% by weight. Amounts should not be employed, however, as would set up a continuous liquid phase in the powder bringing about separation of the dialkyl carbonate therefrom :by drainage. The incorporation of theliquid dialkyl carbonates with the powders may be accomplished in any suitable and convenient way,

for example, by the use of powder-blending ma chines having provision for spraying or otherwise distributing. the liquid uniformly; over the mass of the powder so as to avoid formation of pastes in the mass. For best results, a thorough mixing of the powder and liquid should be obtained.

The term chromogen is used herein in the customar sense of the term to mean those organic compounds which, in themselves not dyestufis, are capable of being converted to dyestuffs by anagency such as oxidation or by coupling with a compound containing one or more auxochrome Under the groups, i. e., auxochromic compounds. term chromogen as definedherein are included leuco vat dyestuffs and their derivatives such as the leuco sulfuric acid esters, which compounds on oxidation are converted to the vat dyestuffs, and the water-soluble stabilized diazo compounds which in aqueous medium, acid, neutral of alkaline as the case may be, couple with auxochromic compounds.

The term auxochromic compound is used herein in the customary sense of the term to mean those organic compoundswhich contain one or more auxochromes which principally are hydroxy, amino and substituted amino groups. Compounds of this kind are for example, resorcinol,

The water-soluble stabilized diazo compounds may be prepared by reacting the diazonium salt in aqueous solution with metal salts such as zinc chloride, cadmium chloride and 'tin chloride or with compounds such as the alkali metal fluoroborates, alkyl or aryl sulfonic acids, e. g., naphthalene-1,5-disulfonic acid, and acid sulfates. These stabilized diazo. compounds exhibit the properties of true salts in that they ionize immediately in neutral or acid solution and show the reaction of diazo ions. Amines which carry one or more water-solubilizing groups such as the sulfonic or carboxylic acid groups to render the stabilized compound'soluble in water may also be used for the preparation of stabilized diazo compounds. Amines of this character are, for example, sarcosine, methyl taurine, N-ethyl or N- methyl-5-suifo-'anthranilic acid, proline and N- methyl glucamine. Depending on whether the amine employed is primary or secondary, the resulting stabilized compound'is' a diazo-amino or a diazo-imino compound. In the art and herein also, these stabilized diazo-amino and diazoimino compounds are contained under the generic or collective term, water-soluble stabilized diazoamino compounds.

The invention and the application of the process thereof to the preparation of dustless powders of organic color compounds, chromogens and auxochromic compounds is illustrated in more detail in the following examples, to which, however, it is not intended that the invention be limited. Parts are by weight.

Example 1 50 parts of a powder of a stabilized diazo compound constituted by the zinc chloride double salt of diazotised 5-nitro-o-anisidine and 1 part of diethyl carbonate are thoroughly mixed by milling together in a small mixing device. The treated powder is non-dusting and has excellent storage stability. 1

Example 2 50 parts of a powder of the azo dye prepared by coupling diazotised p-nitroaniline with dihydroxyethyl-m-toluidine is mixed as in Example 1 with 1 part of diethyl carbonate. The composition is a non-dusting powder.

Example 3 50 parts of a powder of dimethoxy dibenzanthrone is mixed in the manner of the preceding examples with 1 part of diethyl carbonate. The product is outstanding in non-dusting character.

Example 4 50 parts of a powder of diazotised 5-nitro-oanisidine which is stabilized with N-ethyl-5-sulfoanthranilic acid is mixed as before with 1 part of diethyl carbonate. The product is characterized by oustanding non-dusting character.

Example 5 50 parts of a powder of a stabilized diazo compound which is the zinc chloride double salt of diazotised i-chloro-o-nitroanillne is milled in a small mixing device with 2.5 parts of dlethyl carbonate. The product is'of excellent non-dusting character.

Example 6 50 parts of a powder of an azoic dye mixture comprising Naphthol AS--G (bisacetoacet-otoluidide) and diazotised 5-chioro-o-anisidine stabilized with sarcosine is well mixed with 2.5 parts of di-isopropyl carbonate. The composition is a non-dusting powder.

In like manner, the process may be applied for the reduction of dusting in powders of chromogens,-auxochromic compounds and dyestuffs generally, and for the preparation of non-dusting powders of organic pigments, such as azo pigments per se, metal complexes of azo dyestuffs such as the copper or cobalt complexes of the azo dyestuffs obtained by coupling tetrazotised dianisidine or tetrazotised benzidine with 2-naphthol-G-sulfonic acid (Schaefiers salt), phthalocyanine pigments, and color lakes such as those prepared by the deposition on water-insoluble substratum such as barium sulfate of azo dyestuffs, for example, the yellow pigment from the coupling of diazotised o-nitro-p-chloro-aniline with acetoacet-o-chloroanilide. Non-dusting powders of dyestuffs such as methyl violet, crystal violet and the rhodamines, acridine dyestuffs and vat dyestuffs, for example indanthrories, pyranthrones, flavanthrones, dibenzanthrones, anthranthrones, dibenzpyrenequinones, anthrimidecarbazoles, naphthacridones, indigo, thioindigo, indirubin, etc., and their leuco and leuco ester derivaties.

The invention is applicable to the preparation of dustless powder compositions which contain a water-soluble stabilized diazo compound in admixture with a Naphthol-AS type coupler. In its broader aspect the process may be applied in many instances to the binding of dust in powder mixtures of organic color compounds, chromogens or auxochromic compounds which contain other powdered materials useful in the coloring art, such' as dyeing or printing assistants, for example, surface-active agents, e. g., aliphatic acid condensation products of taurine. The same relative proportions of the liquid dialkyl carbonates are applicable in such cases, the total quantity thereof being taken on the weight of the powder mixture.

I claim:

1. A composition of matter comprising a pulw verulent water-soluble stabilized diazo compound which is a salt admixed with an amount of an at least 5 carbon atom liquid dialkyl carbonate, which is not below about 0.5% by weight but is less than would result in liquid separation by drainage.

2. A composition of matter comprising a powder of a water-soluble stabilized diazo compound which is a salt admixed with from about 1 to 5% by weight of an at least 5 carbon atom liquid dialkyl carbonate.

3. A composition of matter comprising a powder of a water-soluble stabilized diazo compound which is a salt admixed with from about 1 to 5% by weight of diethyl carbonate.

4. A composition of matter comprising a powder of a water-soluble double salt of a metal salt and a diazo compound admixed with from about 1 to 5% by weight of an at least 5 carbon atom liquid dialkyl carbonate.

5% by weight of an at least 5 carbon atom liquid dialkyl carbonate.

6. A composition of matter comprising a, pulverulent water-soluble stabilized diazo compound which is a salt of an aryl sulfonic acid admixed with from about 1 to 5 per cent by weight of an at least 5 carbon atom liquid dialkyl carbonate. 7. A composition of matter as defined in claim 6, wherein the liquid dialkyl carbonate is diethyl carbonate.

HERMAN A. BERGSTROM.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,572,715 Gunther Feb. 9, 1926 2,090,511 Crossley Aug. 17, 1937 10 2,138,572 Etzelmiller Nov. 29, 1938 FOREIGN PATENTS Number Country Date 274,642 Germany May 22, 1914 

